Silentmaxx Fanless 400W PSU Review - The Fan
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The Fan
Knowing that the fanless PSU will add more heat to our system, it only makes sense to add an additional intake fan to help push some additional air across those huge heatsinks.
I installed the Silentmaxx 80mm fan in the second intake on the front of the case. The fan is a translucent blue and runs at a fixed speed, though I could find no documentation as to what that speed is. Outside of the case, the fan was very quiet, making less noise than the Ultracool dual-ball bearing, variable speed fans I compared it to. Inside the case, however, the fan was quite noisy. This is likely due to the way the intakes on the case are formed; they are just a series of holes which provide significant resistance to the flow of air. Unfortunately, I didn't have time to mod the case for better air flow (two days of testing were all Dngrswife allowed me to use the family machine).
The temperatures weren't any better, so I pulled the fan out and put a second variable-speed fan into the case. These fans have a remote temperature sensor which was routed to the top-front of the case just below the DVD-RW on either side (the hottest area in the case reachable by the sensors). The fans run at low speed until the sensors read approximately 50° C, where they ramp up to a medium speed. I know someone will ask if I don't mention it, though it isn't relevant here-the speed kicks up at 75°, 100° and 150° C. If your case gets hotter than 75° though, it's time to reconsider your cooling scheme.
With the two fans, the case is quiet. The loudest noise comes from the 60mm output fan at the back of the case. Later, when the computer was placed back into its alcove next to the desk, Dngrswife couldn't even tell that the machine was on. Note that the variable fans also maintained the case and CPU cooler than one variable fan and the Silentmaxx 80.
| | 3.3v | 5v | 12v1 | 12v2 | Case Temp | CPU Temp |
Dual fan (silentmaxx + Ultracool) (DMM) | 3.35 | 5.04 | 12.10 | 12.12 | | |
Dual fan (silent max + Ultracool) | 3.28 | 4.93 | 11.90 | | 43 | 50 |
Dual Ultracool fan (DMM) | 3.35 | 5.04 | 12.12 | 12.11 | | |
Dual Ultracool fan | 3.28 | 4.95 | 11.89 | | 36 | 41 |
Torturing the Power Supply
Regular testing done, I decided to see what would happen if I really heated things up. I unplugged both 80mm fans and allowed the machine to heat up until my CPU reached 60° C. The voltages didn't vary. A quick check of the rails with an oscilloscope showed that noise on the PSU outputs was less than 200mv p-p on any of them. This is not an empirical measurement, as the motherboard and other loads in the computer can also add noise to the rails (particularly fans).
Next: Conclusions >>
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